Cyanoaldehydes and process of producing them



Patented July 18, 1944 GYANOALDEHYDES AND PROCESS OF PRODUCING THEM Herman A. Bruson and Thomas W. Riener, Philadelphia, Pa.,-assignorsto The Rcsinous' Products & Chemical Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Application November 18, 1942,

Serial No. 400,050

, scrum. (01.260-464) This inventionrelates to the preparation of cyanoethyl derivatives of aldehydes.

We have found that aldehydes which have at least two carbon atoms and which are free from interfering acidic groups react with acrylonitrile ,in the presence of alkaline condensing agents to a form cyanoethylated derivatives. I

The reaction is generally applicable to all types of aldehydes having at least two carbon atoms which are free from interfering acidic groups. These aldehydes may possess one or more hydrogen atoms on a carbon atom contiguous to the CH group, as occur, for instance, in the case of aoetaldehyde, methoxyor other alkoxy-acetaldehyde, phenoxyacetaldehyde, aldol, paraldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, hexylaldehyde, heptaldecases crystalline or liquid, to resinous products, depending upon the nature of the aldehyde used and the proportions of acrylonitrile employed. In all cases, however, insofar as the structure formed has been determinable, the products iormed'contain one or more p-cyanoethyl radicals CN-CH:CH:- directly attached to one or more carbon atoms of the original aldehyde employed or of apolymer or condensation product thereof. 1

As alkaline condensing agents for effecting the reaction. there may be used any of the oxides,

V hydroxides, amides, hydrides, or alcoholates of hyde, oleyl aldehyde, octadecylaldehyde, diethyl acetaldehyde, ethyl butyl acetaldehyde, acrolein, crotonaldehyde, methyl propyl acetaldehyde,

cinnamaldehyde, tetrahydroiuriural, cyclohexyl aldehyde, diphenyl acetaldehyde, phenyl acetaldehyde and their homologues. The aldehydes can, however, be devoid of hydrogen on the oncarbon atom, in which case reaction may occur with the hydrogen of the aldehyde group, as in the case 01 benzaldehyde, naphthaldehyde, anthraldehyde and their nuclear substituted derivatives, including, for example, their halogen, alkoxy, or aryloxy derivatives. Furthermore, the reaction is applicable to iuriural, a-methyl-pethyl acrolein, a-methyl acrolein, a-ethyl-p-propyl acrolein, and the like.

In short, the reac-' tion is applicable to aliphatic, cycloaliphatic, aromatic, or heterocyclic aldehydes, saturated or unsaturated, straight chain or branched chain, which are free from acidic groups. Formaldehyde is inoperative for the above reactions.

The aldehydes of the formula wherein R and R are alkyl groups, preferably having at least two carbon atoms in each, are of considerable interest. They yield cyanoethylated products having the formula a CEO R CHICHICN in which the nitrile group ,and the -CH0 group are capable of further reaction. The cyanoethylation products vary from wellthe alkali metals, the alkali metals themselves,

hydroxides oi the alkaline earth metals, or strongly basic quaternary ammonium hydroxides. Typical 01 these agents are sodium and potassium hydroxide, sodiumv methylate, potassium ethylate, barium hydroxide, benzyl trimethyl gammonium hydroxide, etc. The quantity of alkaline condensing agent required is small, amounts from 0.5% to 5% 01' the reactants usually being sumcient. Inert solvents such as benzene, dioxane, tertiary butyl alcohol, or ether can be used to suspend or dissolvethe reactants. The reaction occurs readily at room temperature and is exothermic, so that it is'generallyadvisable to I control the reaction by cooling, at least at the defined organic compounds, which are in many start, aswell as by gradual combination oi'the reactants 'and/or-the use of solvent. the reaction may be initiated at a temperature as low as 0' C. Higher temperatures, even up -to those of a steam bath, may be used to complete the reaction in some cases, but it is generallydesirable to control the temperature to prevent undesirable side reactions. v

The invention is illustrated by the following examples, it being understood that a similar procedure is applicable of the aldehydes used.

Example 1 (a) To a stirredmixture consisting of parts of tertiary butylalcohol, 5 parts of 30% methanolic potassium hydroxide solution, and' 100 parts of freshly distilled diethyl acetalde-- hyde, there was added dropwise 53 parts of acryl- 'onitrile during the course of forty minutes while the reaction mixture was maintained at 3'5?- 38" C. by means of extern'al cooling. The mixture was stirred for three and one-half hour's thereafter at room temperature. Dilute hydrochloric acid was then-added todestroy the al kali and the slightly acidic mixture-was washed to the obvious homoiogues g V menace? v tho ouz 'hly with cold water. The residual oil was or thirty minutes while the reaction teninerature then distilled in vacuum. was maintained at 35-38 C. The mixture was The product, a-(Z-cyanoethyI) a ethyl buthen stirred for one and one-half hours longer tyraldehyde, at room temperature, after which it was acidified 5 with dilute hydrochloric acid and then washed with water and dried in vacuurnto yield 123 parts of fiai'yfially 'gfirystalli Aloohol was added tind'a crystalline material (18 parts) was filtered off. After recrystallization from ethanol, 'E'thls product formed colorless needles, with a tillation, it boiled at 128/4 mm (b) In a similar manner, meth aldehyde yields a-(Z-cyanoeth l) -a aldehyde as a colorless oil. I

Example (a) Acrylonitrile (53 parts) was added gradually during one-half hour to a stirredymixture. consisting of 128 parts of freshly distill ethyl acetaldehyde, 1001parts of tertiary bu l alcohol, and 10 parts of 30% methanoli'c botas n point 225-24o/s mm.

boiling point 240-290/6 mm.

pen tion, fraction I yielded a cut (28 parts) boiling at 230-235/6 mm., as a pale yellow 'o'il containing 14.2% C1 and 11.03% N by so 1. .COld, rystallizatlon n'om, ethanol;

aldehyde,

ni-i iitu e cons su g 4 oil? inxazgyield rofis1'36c-partsit1boi1,ed;-ata140%142 /5mm 1 ;-(b)-;In::a similarlmanner methy phenyl ace aldehydeayields" @-:(-2 'cyanoethyl) methyi'a'phe" nylacetaldehyderasoa olorless' oil;

D n redistillatiom lAcrylonitrile- 1 tqca stirred ;.r pixtur to 935;- pl r rlbenz dehydei onrartao -sqll um hydrpx e .,w

ma ta nsa,

zen by analysis.

ethylatlon product.

Fraction II, upon redi s tilla t ipn, yielded a fraction boiling at 2'10 3 which rapidly solidi- A m tu e 01' 86 parts of ls tyraldehyde and parts: of tertiary ;butyl l. an :p methanolicrfiil %ll notes? slum hyd I the-temperature.was .main-- tained at 1020 C. by spoqling jlfter all of the aldehyde and nitrile had been added, the reaction mixture was stirred for one hour longer at 5-10 orthfcfich loro C. and was thena-reacidi-fied with dilute hydrobli ,s bjh 1 19 319 aq dswe ll slmand i ,ti, esi

The 'cy'anothylat ed p boilsat i1 0.

assaes'r Trample 8 Acrylonitrile (26 parts) was added dropwise to a stirred solution of 100 parts of a-amyl cinnamaldehyde, 100 parts of tertiary butyl alcohol, and parts of methanolic 30% potassium hydroxide at 30-35 C. The mixture was then stirred for two hours at room temperature, neutralized with dilute hydrochloric acid, washed, and distilled in vacuum.

Two main liquid fractions were collected, one of which (a) distilled at 220-260 8 mm. and the other (b) at 260-290/8 mm. Upon refractionation (a) yielded a cyanoethylated yellow oil boiling at 205225./5 mm. and (b) yielded a cyanoethylated red oil, boiling at 260-265 C./6 mm,, containing 7.7% of nitrogen by analysis.

Example 9 A mixture of 70 parts of crotonaldehyde and 106 parts of acrylonitrile was added dropwise during forty-five minutes to a stirred solution of 5 parts of methanolic potassium hydroxide dissolved in 100 parts or tertiary butyl alcohol while the reaction mixture was cooled to 1015 C. The mixture was then stirred for eight hours at room temperature, and the dark red product acidified with dilute hydrochloric acid, washed with water, and dried in vacuum at 100 C. The cyanoethylated product was a dark red, viscous balsam containing about 7.6% of nitrogen by analysis.

The products obtained by the process herein described are useful as intermediates for the preparation of resins, insecticides, drugs, and many other technical purposes.

We claim:

1. The method of cyanoethylating a dialkyl acetaldehyde which comprises reacting a dialkyl acetaldehyde with acrylonitrile in the presence of an alkaline condensing agent.

2. The method for preparing a cyanoethyl aldehyde having the formula:

11\ /CHO R CHzCHtCN wherein R and R are each alkyl groups, which comprises reacting acrylonitrile in the presence of an alkaline condensing agent with a dialkyl 'acetaldehyde having the formula:

wherein R and R are each alkyl groups.

3. The method for preparing cyanoethyl aldehydes having the formula: R\ cno R1 omcmcN ethyl hexaldehyde with acrylonitrile in the presence of an alkaline condensing agent.

6. As a new chemical compound, a cyanoethylated dialkyl acetaldehycle having the formula:

R\ CEO R CHaCHlCN wherein R and R are each alkyl groups.

7. As a new compound, a-(2-cyanoethyl) ethyl butyraldehyde,

CHICK! CHO CHO

omcmomcn crncrnon HERMAN A. BRUSON. THOMAS W. RJENER. 

